Lipoic acid and carnitine combo show diabetes potential

A combination of lipoic acid and acetyl-L-carnitine may boost the
function of mitochondria - the cell's power stations - suggests
research with implications for diabetes and obesity.

Researchers, led by Jiankang Liu from the Institute for Brain Aging
and Dementia at the University of California (Irvine), report that
the nutrients work together, or synergistically - a result not
previously reported.
"The strong synergistic effect of the combination of LA and ALC
in [fat cells] adipocytes suggests that these two nutrients
complement each other's function in mitochondrial biogenesis,"​
wrote the authors in the journal Diabetologia.​
Talking to NutraIngredients.com, Liu said: "The paper in
Diabetologia is the first paper using adipocytes showing that the
combination of alpha-lipoic acid and acetyl-L-carntitine may be
more effective than individuals to ameliorating diabetes and
obesity and also elucidating the mechanisms of the mitochondrial
biogenesis synergistically." ​
Lipoic acid (LA) has been linked to a host of health benefits,
including enhancing heart and artery health, immune and brain
functions and has been shown to support weight reduction.
Likewise, carnitine, a "conditionally essential nutrient" is an
increasingly popular ingredient in dietary supplements intended for
weight loss and sports. Three different forms of the compound are
commonly available: L-carnitine (LCAR), acetyl-L-carnitine (ALCAR),
and propionyl-L-carnitine (PLCAR), although the latter is only
available in Europe. There is no evidence to suggest that there is
any inherent differences between the forms.
A risk assessment from scientists at the Council for Responsible
Nutrtion (CRN), published in the journal Regulatory Toxicology
and Pharmacology​ (doi: 10.1016/j.yrtph.2006.06.007) reported
that an adult human observed safe limit (OSL) of 2000 mg for the
nutrient.
The new study measured the activity of mitochondria in adipocytes
in the presence of LA and/or LCAR at a concentration of 0.1, 1 and
10 micromoles per litre for 24 hours. The mass of the mitochondria
and their oxygen consumption were measured, in addition to several
genetic markers.
Liu and co-workers report that the combination of LA and LCAR
increased the mass, oxygen consumption, mitochondrial DNA
expression, and fatty acid oxidation in the fat cells.
"However, the treatments with LA or ALC alone at the same
concentrations showed little effect on mitochondrial function and
biogenesis,"​ noted the researchers.
Speaking to this website, Dr. Liu noted: "Lipoic acid and
acetyl-L-carnitine have become very hot after our reports on the
complementary effects on improving memory and ambulatory activity
in old rats,"​ relating to studies published in the
Proceedings of the National Academy of Science​ in 2002
(Vol. 99, Pages 1870-1875, 1876-1881, and 2356-61).
Looking ahead to the next stage of the research, the scientists
said that the combination of the nutrients should be tested in
animals with insulin resistance. This would enable them to
"determine whether such combinations might be an effective
nutrient intervention for ameliorating mitochondrial
dysfunction​ in vivo."​
An estimated 19 million people are affected by diabetes in the EU
25, equal to four per cent of the total population. This figure is
projected to increase to 26 million by 2030.
In the US, there are over 20 million people with diabetes, equal to
seven per cent of the population. The total costs are thought to be
as much as $132 billion, with $92 billion being direct costs from
medication, according to 2002 American Diabetes Association
figures.
Source: Diabetologia​
2008, Volume 51, Pages 165-174, doi:
10.1007/s00125-007-0852-4
"R-alpha-Lipoic acid and acetyl-L-carnitine complementarily
promote mitochondrial biogenesis in murine 3T3-L1
adipocytes" ​Authors: W. Shen, K. Liu, C. Tian, L. Yang,
X. Li, J. Ren, L. Packer, C.W. Cotman, J. Liu